Resolving Environmental and Grid Reliability Conflicts Act of 2015 This bill amends the Federal Power Act with respect to orders by the Federal Energy Regulatory Commission (FERC) to generate, transmit, or sell electricity to prevent an emergency in energy reliability, where the order may result in a conflict with environmental law. FERC must ensure that the order: (1) requires generation, delivery, interchange, or transmission of electricity only during hours necessary to meet the emergency and serve the public interest; and (2) be consistent with applicable environmental law and minimize any adverse environmental impacts to the maximum extent practicable. Compliance with such an order shall not be considered a violation of conflicting federal, state, or local environmental laws. Orders that may result in a conflict with environmental law must expire within 90 days and may be renewed or reissued for subsequent periods as necessary to meet the emergency and serve the public interest. During an emergency, a municipality engaged in the transmission or sale of electricity and not otherwise subject to FERC's jurisdiction may make temporary connections with public utilities subject to FERC's jurisdiction and construct temporary facilities for the transmission of electricity in interstate commerce as may be necessary or appropriate to meet the emergency.